Nanogels of cholesterol-bearing pullulan modified with amino-groups (CHPNH(2)) were utilized as a career to introduce quantum dots (QDs) into periodontal ligament (PDL) cells. Nanogel-QD effectively labeled PDL cells over 3 weeks. These results indicate that CHPNH(2)nanogels have a potential as a research tool in the studies of intracellular delivery system.